1. Field of the Invention
The present invention relates to technologies of reading images using a plurality of light-emitting elements.
2. Description of the Related Art
Accompanying light power increases in white LEDs (light-emitting diodes) in recent years, these have begun to be employed as a light source for copiers and scanners in which light collection type sensors (CCD and CMOS image sensors) are used. Generally, since light collection type sensors require a high light power, a required light power is created by arranging a plurality of white LEDs side by side in a reading direction.
Various recovery methods have been proposed for white LEDs used in copiers and scanners so that when a single white LED has failed, the other while LEDs do not become unusable. For example, as a conventional technology 1, there is a method in which a determination is made as to whether or not a failed LED is positioned within a size of an original document, such that reading continues if it is outside the size, and reading is interrupted if it is inside the size, and a warning message is displayed to a user. Furthermore, as a conventional technology 2, there is a method in which in a case where 3-color RGB LEDs are used as light sources and an LED of one color has failed, reading of color images is interrupted, but reading is carried out of only monochrome images.